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109 lines
2.9 KiB
109 lines
2.9 KiB
15 years ago
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/* This file is part of indexlib.
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* Copyright (C) 2005 Luís Pedro Coelho <luis@luispedro.org>
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*
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* Indexlib is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License, version 2, as
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* published by the Free Software Foundation and available as file
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* GPL_V2 which is distributed along with indexlib.
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*
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* Indexlib is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
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* MA 02110-1301, USA
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*
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* In addition, as a special exception, the copyright holders give
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* permission to link the code of this program with any edition of
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* the Qt library by Trolltech AS, Norway (or with modified versions
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* of Qt that use the same license as Qt), and distribute linked
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* combinations including the two. You must obey the GNU General
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* Public License in all respects for all of the code used other than
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* Qt. If you modify this file, you may extend this exception to
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* your version of the file, but you are not obligated to do so. If
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* you do not wish to do so, delete this exception statement from
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* your version.
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*/
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#include "bitstream.h"
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#include "logfile.h"
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#include "format.h"
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#include <assert.h>
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bitstream::bitstream( unsigned char* data, unsigned size )
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:bytes_( data ),
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writeable_( true ),
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size_( size ),
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cur_( 0 ) { }
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bitstream::bitstream( const unsigned char* data, unsigned size )
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:bytes_( const_cast<unsigned char*>( data ) ),
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writeable_( false ),
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size_( size ),
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cur_( 0 ) { }
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bool bit( unsigned v, unsigned idx ) {
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return ( v >> idx ) & 1;
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}
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bitstream& bitstream::operator << ( uint16_t x ) {
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for ( unsigned i = 0; i != 16; ++i ) putbit( bit( x, i ) );
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return *this;
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}
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bitstream& bitstream::operator << ( uint32_t x ) {
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for ( unsigned i = 0; i != 32; ++i ) putbit( bit( x, i ) );
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return *this;
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}
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bitstream& bitstream::operator >> ( uint16_t& v ) {
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v = 0;
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for ( int i = 0; i != 16; ++i ) {
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v <<= 1;
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v |= getbit();
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}
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return *this;
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}
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bitstream& bitstream::operator >> ( uint32_t& v ) {
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v = 0;
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for ( int i = 0; i != 32; ++i ) {
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v <<= 1;
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v |= getbit();
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}
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return *this;
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}
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void bitstream::putback( uint16_t ) {
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assert( cur_ >= 16 );
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cur_ -= 16;
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}
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void bitstream::putback( uint32_t ) {
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assert( cur_ >= 32 );
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cur_ -= 32;
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}
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bool bitstream::getbit() {
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unsigned inbyte = cur_ % 8;
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unsigned byte = cur_ / 8;
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++cur_;
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return ( bytes_[ byte ] >> inbyte ) & 1;
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}
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void bitstream::putbit( bool value ) {
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unsigned inbyte = cur_ % 8;
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unsigned byte = cur_ / 8;
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assert( byte < size_ );
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if ( value ) bytes_[ byte ] |= ( 1 << inbyte );
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else bytes_[ byte ] &= ~( 1 << inbyte );
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++cur_;
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}
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